There has been a longstanding need for a simple and effective means to remove hard-water deposits from many surfaces, such as windows, chrome, shower doors, tubs, sinks and fixtures. Available products designed for this purpose are either of industrial strength (thus dangerous to use unless proper precautions are observed), or do not effectively aid in the cleaning of hard-water build-up without substantial effort by whoever is charged with the task. In addition, there is a problem of retaining such products on a vertical surface in a film of sufficient thickness and body to clean the surface.
A thixotropic gel cleaning product (metal cleaner) is described in U.S. Pat. No. 2,672,449. That thixotropic gel is designed to clean oxide deposits from a metal surface. It does not rinse well with water and its safety for household use is regarded as at least questionable. The recommended Triton surfactant requires great care when it is used. The gel also contains bentonite as a mild abrasive and polishing agent. However, bentonite does not have enough abrasive power to clean and polish surfaces having hard-water deposits. The bentonite is also used for its gel forming properties; if another material were substituted for the bentonite, in regard to abrasive purposes, the entire cleaning gel composition would have to be redesigned.